1. Field of the Invention
This invention relates to elongated edging or holding devices having particular utility for holding landscaping and/or paving materials in place in defined areas. In particular the invention relates to such devices which are flexible and economical to install and which adapt readily to various shapes of areas. Even more particularly the invention relates to a novel connector structure whereby a plurality of the devices may be readily arranged in end-to-end relationship and held securely together in an edge defining array.
2. The Prior Art Background
Elongated landscape retaining or edging strips are elongated barriers installed longitudinally along the surface of the ground such that the barrier is substantially perpendicular to the ground. Such edging strips are used in diverse applications including such things as the retention and/or separation of beds of earth or other landscaping fill (i.e., gravel, decorative rock, bark, dirt, sand, mulch) or the retention and maintenance of paving materials, (i.e., bricks, paving stones, rock, gravel, etc.).
Restraining strips that are secured to the ground for holding paving and landscape materials in place have been used for ages. Many of these prior art devices are difficult to install and sometimes require the digging of trenches for installation. Moreover, such retaining strips, while sometimes bendable in a horizontal plane perpendicular to the ground, often lack the vertical flexibility needed to conform to changes in ground slope while maintaining a perpendicular relationship between the ground surface and the retaining strip barrier. Such inflexibility sometimes necessitates the inclusion of a vertically angled joint to accommodate a significant change in ground slope. And even when such joints are used, the inability of a given strip to conform to changes in ground slope will result in occasional gaps between the ground and the strip. Grass and/or debris can encroach underneath the strip through such gaps. These prior art devices also generally are susceptible to a serious problem of tending to pull up out of the ground, particularly when the ground is subject to heaving by freezing or changes in moisture content. Many of the prior devices consist of relatively complicated assemblies such that the precise alignment and overlap of a relatively large number of segments is unnecessarily complicated, time-consuming, and tedious.
Landscape restraining strips must have sufficient mechanical strength to avoid gross deformation by downward or lateral forces. Such strength is particularly critical when the landscape edging devices are used to retain such things as, for example, the gravel in gravel walkways, because of the tendency of the gravel to shift laterally when it is walked upon. However, flat vertical wall restraining strips of the past that have adequate mechanical strength to withstand this lateral force are generally not sufficiently flexible to allow the same to conform easily to changes in ground slope.
Another problem with prior art edging devices is that for practical reasons the same must be made in smaller lengths and must therefore be connected together usually at the job site. Present day connectors are often deficient and incapable of totally resisting the multitude of forces which are imposed on the devices during installation and use. That is to say, while a given device might be capable of resisting forces or twisting imposed in one direction, the same device might be incapable of resisting forces or twisting imposed in a different direction. This is particularly true when one considers the forces imposed on the connectors used for connecting a plurality of separate lengths of edging together and holding the same in alignment. Accordingly, there has been a long standing need for the provision of edging devices which are readily yet sturdily interconnectable in end-to-end relationship.
Prior art edging devices are shown in U.S. Pat. No. 5,240,343, U.S. Pat. No. 5,375,941, U.S. Pat. No. 6,071,038, Re 33,550, U.S. Pat. No. 6,767,159 and U.S. Pat. No. 6,409,421. The entireties of the disclosures of these enumerated patents are incorporated herein by this specific reference thereto.